The present invention relates to an eyeglass frame shape measuring apparatus to measure (trace) a shape of a rim of an eyeglass frame.
There is known an eyeglass frame shape measuring apparatus that includes a frame holding mechanism which holds left and right rims (lens frames) of an eyeglass frame in the desired state, and a measurement mechanism (tracing mechanism) to obtain a three-dimensional shape of the rim by moving a tracing stylus, which is inserted into a groove (bevel groove) of the rim, along the bevel groove of the rim, and detecting a movement position of the tracing stylus in a radial direction and a direction vertical to a radial direction of the rim (for example, JP-A-2000-314617 and JP-A-2011-122899). The frame holding mechanism includes a clamping mechanism which is disposed on a front side and a rear side of the rim to clamp the rim with two clamping pins. When the tracing stylus is inserted into the groove of the rim, the tracing stylus is generally positioned in the center of the two clamping pins in a direction vertical to the radius vector such that the tracing stylus is positioned in the center of a front-to-rear width (front side and rear side) of the rim. Then, the tracing stylus is inserted into the bevel groove by moving the tracing stylus to the rim side.